WO2023176939A1 - Laser emission spectrophotometry optical device, laser emission spectrophotometer, laser emission spectrophotometry method, and molten metal plating facility - Google Patents

Abstract

[Problem] To realize light weight, small size, and sufficient analysis accuracy. [Solution] This laser emission spectrophotometry optical device includes: a housing unit including a laser oscillator that oscillates laser light, one condenser lens that condenses the laser light and on which the laser light emitted from the laser oscillator is directly incident, and an optical fiber light receiving part that receives, on a light receiving end surface, emitted light radiated from plasma generated by radiating the laser light onto molten metal, and that guides the light to an exit-side end surface; and a cylindrical probe that is connected to the housing unit such that a center shaft is parallel to an oscillation axis of the laser light in the laser oscillator, that supplies inert gas toward an opening end positioned on a downstream side of the traveling direction of the laser light, and that guides the laser light to the opening end to radiate the laser light onto the molten metal. A surface normal direction at the light receiving end surface of the optical fiber light receiving part is parallel to the oscillation axis of the laser light.

Description

Optical device for laser emission spectrometry, laser emission spectrometer, laser emission spectrometry method, and molten metal plating equipment

The present invention relates to an optical device for laser emission spectrometry, a laser emission spectrometer, a method for laser emission spectrometry, and molten metal plating equipment.

In molten metal baths such as hot-dip galvanizing baths, constituent components must be monitored in order to control the quality of products obtained using such molten metal baths (for example, hot-dip galvanized steel sheets, etc.) and to manage operational conditions. , management is required.

For example, in the hot-dip galvanizing manufacturing process, a small amount of Al or Fe is added to the hot-dip galvanizing bath in order to optimize the plating film and steel sheet and improve the anticorrosion effect. As the steel sheet passes through the hot-dip galvanizing bath during operation, Al tends to decrease and Fe tends to increase.

If the content of trace elements in the hot-dip galvanizing bath deviates from the appropriate range, it may cause poor plating, or these trace elements may alloy with zinc to form dross, which may hinder operations. There is sex. Therefore, it is important to control the content of these trace elements by continuously analyzing them, and to add trace elements to an appropriate range and remove formed dross.

As a method for analyzing the content of such trace elements, Patent Document 1 below proposes a method and apparatus for laser emission spectroscopy of molten metal. Furthermore, Patent Document 2 below discloses a method and apparatus in which laser-induced breakdown spectroscopy (LIBS) is applied to the analysis of a molten material.

Japanese Patent Application Publication No. 2006-300819 Special Publication No. 2005-530989

However, the devices proposed in Patent Document 1 and Patent Document 2 are both large and heavy. Therefore, a great deal of effort is required to remove, transport, and install the device, for example, in order to change the observation position of the molten metal bath. Furthermore, depending on the configuration of the molten metal bath, there may be restrictions on the mounting position of the device. For example, even if the conventional device configuration was miniaturized, the size limit was 500 mm (width) x 250 mm (height) x 640 mm (depth).

Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a laser emission spectrometer that is lightweight, compact, and capable of achieving sufficient analytical accuracy. An object of the present invention is to provide an optical device for use, a laser emission spectroscopic analysis device, a laser emission spectroscopic analysis method, and molten metal plating equipment.

In order to solve the above problems, the inventors of the present invention have made extensive studies and found that an optical system for guiding the laser beam emitted from a laser oscillator in a desired state while maintaining sufficient measurement accuracy, and a laser beam When receiving the light emitted from the plasma generated by irradiating the target object with light, we omit as much as possible what was considered to be essential, such as an optical system for concentrating the light emitted. We found that by doing so, it is possible to significantly reduce the weight and size of the device.
The gist of the present invention, which was completed based on this knowledge, is as follows.

(1) An optical device used to analyze the components of molten metal, which includes a laser oscillator that emits a laser beam, and a device that focuses the laser beam, and which collects the laser beam emitted from the laser oscillator. an optical fiber light receiving section that receives light emitted from plasma generated by irradiating the molten metal with the laser light at a light receiving end surface; The inert gas is connected to the housing portion so that the axis is parallel to the oscillation axis of the laser beam in the laser oscillator, and the inert gas is supplied toward an open end located downstream in the direction of travel of the laser beam. and a cylindrical probe that guides the laser beam to the open end and irradiates the molten metal, the surface normal direction of the light receiving end surface of the optical fiber light receiving section being aligned with the oscillation axis of the laser beam. Parallel optical device for laser emission spectroscopy.
(2) The optical device for laser emission spectroscopy according to (1), wherein the cylindrical probe is connected to the housing so that its central axis is coaxial with the oscillation axis of the laser beam.
(3) The optical device for laser emission spectroscopy according to (1) or (2), wherein the condensing lens is provided at a connecting portion between the housing portion and the cylindrical probe.
(4) For laser emission spectroscopic analysis according to any one of (1) to (3), at least a part of the emitted light is incident on the light receiving end face of the optical fiber light receiving part in an uncondensed state. optical equipment.
(5) The optical device for laser emission spectroscopy according to any one of (1) to (4), wherein the laser oscillator is a diode-excited laser oscillator.
(6) The optical device for laser emission spectrometry according to any one of (1) to (5), wherein the condenser lens has an antireflection film on its surface that prevents reflection of the laser beam.
(7) The laser according to any one of (1) to (6), further comprising an angle adjustment mechanism that adjusts the lens optical axis direction of the condenser lens by changing the attachment angle of the condenser lens. Optical device for emission spectroscopy.
(8) The optical device for laser emission spectroscopic analysis according to any one of (1) to (7), a spectroscopic optics section that spectrally spectra the light emitted guided by the optical fiber light receiving section, and the spectroscopic optics section. A laser emission spectrometer comprising: a detector that detects the luminescence spectrally separated by the detector; and a component analysis section that analyzes the components of the molten metal based on the detection result of the luminescence by the detector.
(9) The laser emission spectrometer according to (8), wherein the detector is an image intensifier charge-coupled device detector.
(10) The laser emission spectrometer according to (8) or (9), further comprising a cooling mechanism that cools the inside of the housing.
(11) A method for laser emission spectrometry, comprising analyzing molten metal in a plating bath for molten metal plating using the laser emission spectrometer according to any one of (8) to (10).
(12) The laser emission spectrometry method according to (11), wherein the hot-dip metal plating is hot-dip galvanizing.
(13) A molten metal plating facility comprising the laser emission spectrometer according to any one of (8) to (10).
(14) The hot-dip metal plating equipment according to (13), which is a hot-dip galvanizing equipment for performing hot-dip galvanizing.

As explained above, according to the present invention, an optical device for laser emission spectrometry, a laser emission spectrometer, and a laser emission spectrometry method are lightweight and compact, and can achieve sufficient analytical accuracy. , and it becomes possible to provide hot-dip metal plating equipment.

FIG. 1 is an explanatory diagram schematically showing an example of the configuration of an optical device for laser emission spectrometry according to an embodiment of the present invention. FIG. 2 is an explanatory diagram schematically showing another example of the configuration of the optical device for laser emission spectroscopy according to the same embodiment. 1 is a block diagram schematically showing an example of the configuration of a laser emission spectrometer according to the same embodiment. FIG. FIG. 2 is a block diagram showing an example of the configuration of a processing unit included in the laser emission spectrometer according to the embodiment. FIG. 2 is a block diagram showing an example of the hardware configuration of an arithmetic processing unit according to the same embodiment. FIG. 2 is an explanatory diagram schematically showing an example of hot-dip galvanizing equipment as an example of hot-dip metal plating equipment according to the embodiment. 1 is a laser-induced breakdown spectrum showing signal intensities of Al and Zn for a hot-dip galvanizing bath measured in an example. It is a graph diagram showing the time course of Al concentration in a hot-dip galvanizing bath measured in an example.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals and redundant explanation will be omitted.

(About optical equipment for laser emission spectroscopy)
First, an optical device for laser emission spectroscopy according to an embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is an explanatory diagram schematically showing an example of the configuration of an optical device for laser emission spectroscopy according to the present embodiment.

The optical device 1 for laser emission spectroscopy shown in FIG. 1 is an optical device used to analyze the components of a target object (more specifically, molten metal), and is used in so-called laser-induced breakdown spectroscopy (LIBS). This device is used as a measurement probe for a laser emission spectrometer to perform

The optical device 1 for laser emission spectrometry supplies an inert gas from a cylindrical probe 20, and irradiates a target object with pulsed laser light emitted by a laser oscillator 12, thereby creating a connection between the target object and the inert gas. This is a device that receives light emitted from plasma generated at an interface (hereinafter also referred to as plasma light).

As shown in FIG. 1, the optical device 1 for laser emission spectrometry includes a housing 10, a cylindrical probe 20, and a hood 30.

As shown in FIG. 1, the housing section 10 includes a housing 11, a laser oscillator 12, a condensing lens 13, and an optical fiber light receiving section 14.
The housing 11 is a casing, and houses the laser oscillator 12 and at least the light receiving section 143 of the optical fiber light receiving section 14 in the internal space 111 thereof. In this embodiment, the housing 11 has its longitudinal direction substantially parallel to the laser oscillation axis A, and the condensing lens 13 is fixed at its tip side. On the other hand, the housing 11 has an opening 113 on its base end side, and the opening 113 functions as a work space for maintenance of the laser oscillator 12 and also serves as a passage for wiring, etc. (not shown). Furthermore, the opening 113 also functions as a refrigerant outlet from the cooling mechanism 40, which will be described later.

The housing 11 can be made of known materials such as various resin materials or metal materials. Further, the housing 11 is smaller than the housing of a conventional optical device for laser emission spectrometry analysis for reasons described later.

The laser oscillator 12 is a device that oscillates pulsed laser light (hereinafter also simply referred to as "laser light"). Since the laser oscillator 12 is required to function as an illumination light source for LIBS analysis, the laser oscillator 12 is required to function as an illumination light source for LIBS analysis. It is required to have a pulsed laser beam oscillation function capable of evaporating each component (e.g., etc.) without selectivity. As such a laser oscillator 12, it is possible to use various pulsed laser light sources that oscillate a high-power pulsed laser that enables LIBS analysis. Examples of such pulsed laser light sources include solid lasers such as ruby lasers, Ti sapphire lasers, and YAG lasers; gas lasers such as _CO2 gas lasers, Ar ion lasers, He-Ne ion lasers, and excimer lasers; Examples include semiconductor lasers and fiber lasers.

In the optical device 1 for laser emission spectroscopy according to the present embodiment, it is particularly preferable to use a diode-excited laser oscillator as the laser oscillator 12. A diode-pumped laser oscillator is an oscillator that has excellent stability in the single pulse it oscillates. In LIBS, since analysis is performed for each pulse, the stability of each pulse of laser light is further improved, and as a result, it is possible to further improve analysis accuracy.

Additionally, a diode-pumped laser oscillator can reduce the frequency of oscillator maintenance compared to a commonly used flashlamp-pumped laser oscillator. The optical device 1 for laser emission spectroscopy according to the present embodiment is configured such that the laser beam emitted from the laser oscillator 12 directly enters the condensing lens 13, which will be described later. It is necessary to precisely adjust the laser oscillation axis A. By using a diode-pumped laser oscillator, the frequency of maintenance can be reduced, and the frequency of adjustment of the laser oscillation axis A can also be reduced, which not only improves convenience for users but also eliminates the problem caused by variations in the laser oscillation axis A. It becomes possible to suppress variations in measurement accuracy.

The laser oscillator 12 is arranged within the housing 11 so that the laser oscillation axis A of the laser beam is substantially parallel to the central axis of the cylindrical probe 20. As a result, in this embodiment, the laser light emitted from the laser oscillator 12 is guided directly to the cylindrical probe 20 without using a conventionally used light guiding optical system such as a laser reflecting mirror. Ru. Further, it is more preferable that the laser oscillation axis A of the laser beam be arranged so as to be substantially coaxial with the central axis of the cylindrical probe 20. This makes it possible to reliably guide the laser light emitted from the laser oscillator 12 to the object without wasting it.

Generally, the position and angle of the laser oscillation axis are extremely important in laser emission spectroscopic analysis, and in order to adjust the position and angle of the laser oscillation axis, it has traditionally been necessary to use a light guiding optical system such as a laser reflecting mirror. It has been thought that. In particular, when analyzing molten metal in a molten metal plating bath, etc., it is necessary to analyze the molten metal at a relatively deep position in the bath. Probes tend to be relatively long. In such cases, considering the possibility that the laser oscillation axis may shift and the laser beam is inadvertently irradiated onto the cylindrical probe, the importance of a light guide optical system such as a laser reflection mirror is important when analyzing other objects. It is generally considered that this is larger than when Contrary to the conventional common sense recognition of those skilled in the art, the present inventors have discovered that light guiding optics such as a laser reflecting mirror are used in a device having a relatively long cylindrical probe for targeting molten metal, etc. It has been found that even if the system is omitted, the position and angle of the laser oscillation axis can be set to a level that poses no problem for measurement. By omitting a light guiding optical system such as a laser reflecting mirror in this way, it is possible to make the optical device for laser emission spectroscopy smaller and lighter.

Further, the laser oscillator 12 may be fixed to the housing 11 by a fixing member (not shown) that can adjust the position of the laser oscillator 12. Thereby, the position of the laser oscillator 12 can be adjusted, and the position and angle of the laser oscillation axis can be adjusted.

The condensing lens 13 is placed on the laser oscillation axis L on the tip side of the housing 11, and the laser beam emitted from the laser oscillator 12 directly enters the lens surface. The condensing lens 13 condenses the laser beam emitted from the laser oscillator 12 and guides the laser beam to the cylindrical probe 20 .

The laser beam condensed by the condenser lens 13 is generally required to be focused near the opening end 24 of the cylindrical probe 20, which will be described later, and more preferably further forward in the traveling direction of the laser beam than the opening end 24. It will be done.

In addition, as shown in FIG. 1, the condensing lens 13 according to the present embodiment is connected to the boundary with the cylindrical probe 20 in the housing 11 (the connection part of the cylindrical probe 20) using an O-ring (not shown) or the like. ). Thereby, the condensing lens 13 not only functions as a light guide window that partitions the internal space 111 of the housing 11 and the space inside the cylindrical probe 20, but also functions as a light guide window for partitioning the interior space 111 of the housing 11 and the space inside the cylindrical probe 20. can be prevented from entering the internal space 111 of the housing 11. Furthermore, by providing the condensing lens 13 with multiple roles as described above, it is possible to omit the arrangement of a separate light guide window, and the weight of the optical device 1 for laser emission spectrometry can be further reduced. becomes possible.

Note that the condensing lens 13 may be a lens group composed of a plurality of lenses. However, from the viewpoint of further reducing the weight of the optical device 1 for laser emission spectroscopy, it is more preferable that the condenser lens 13 is composed of one lens.

Further, the condenser lens 13 may be fixed to the housing 11 by a fixing member (not shown) that can adjust the attachment angle of the condenser lens 13. Such a fixing member functions as an angle adjustment mechanism that adjusts the lens optical axis direction of the condensing lens 13, making it possible to adjust the position and angle of the laser oscillation axis. This makes it possible to finely adjust the laser oscillation axis even when the laser beam oscillated from the laser oscillator 12 is directly incident on the condenser lens 13, making it possible to further improve measurement accuracy. Become.

Furthermore, it is preferable that at least the surface 131 of the condensing lens 13 on the cylindrical probe 20 side is provided with an antireflection film to prevent reflection of laser light. This can prevent the laser beam reflected by the surface 131 of the condensing lens 13 from directly reaching the laser oscillator 12 and damaging the laser oscillator 12.

As such an anti-reflection film, it is possible to use various known anti-reflection films, including, for example, a dielectric multilayer film in which dielectric films are laminated in multiple layers.

The optical fiber light receiving unit 14 receives light emitted from plasma (plasma light) generated by irradiating a target object with laser light at its light receiving end surface. As shown in FIG. 1, the optical fiber light receiving section 14 includes a bundle fiber 141, which is a bundle of optical fibers, a light receiving section 143, and a light emitting section 145.

The light receiving section 143 is connected to one end of the bundle fiber 141, and at least the light receiving section 143 of the optical fiber light receiving section 14 is housed inside the casing 11. In the optical device 1 for laser emission spectroscopy according to the present embodiment, the light receiving section 143 has a surface normal direction parallel to the laser oscillation axis A at the light receiving end surface 144 of the light receiving section 143, as schematically shown in FIG. It is set up so that As a result, at least a portion of the plasma light enters the light receiving end surface 144 of the light receiving section 143 without being condensed.

Here, "the surface normal direction of the light-receiving end surface 144 is parallel to the laser oscillation axis A" means not only when the surface normal direction and the laser oscillation axis A are completely parallel, but also when the surface normal direction is parallel to the laser oscillation axis A. This also includes cases where the angle is tilted by a certain permissible angle with respect to the laser oscillation axis A. As a result of studies conducted by the present inventors, if the angle between the surface normal direction and the laser oscillation axis A is within 10 degrees, plasma light sufficient to perform LIBS analysis with the required accuracy can be received. was possible. The closer the angle between the surface normal direction and the laser oscillation axis A becomes parallel, the more the detection intensity of plasma light can be increased. The angle between the surface normal direction and the laser oscillation axis A is preferably 1.0° or less, more preferably 0.6° or less.

The plasma light generated by irradiating a target object with laser light is weak. Therefore, in order to perform accurate analysis, it has traditionally been thought that it is necessary to collect the plasma light using a focusing optical system consisting of lenses, etc., and to detect as much of the generated plasma light as possible. I've been exposed to it. However, the present inventors have discovered that these condensing optical systems can be omitted and the plasma light can be made to enter the light-receiving end surface 144 of the light-receiving section 143 without being condensed. This makes it possible to significantly reduce the weight and size of the optical device 1 for laser emission spectroscopy.

Furthermore, in this embodiment, the plasma light received by the light-receiving end face 144 of the light-receiving section 143 is not focused, and thus becomes part of the entire generated plasma light. However, when condensing and receiving plasma light, if the optical axis of the laser light shifts, the fluctuations in the obtained signal intensity will become larger. Therefore, in the case of this embodiment in which only a part of the plasma light is received without condensing the light, the present inventors believe that the effects of heat-induced distortion, vibration, and bath surface fluctuations on the analysis results in the molten metal plating equipment We found that it is possible to suppress

In the optical fiber light receiving section 14, the bundle fiber 141 transmits the plasma light received by the light receiving end surface 144 of the light receiving section 143 to the emitting section 145. A spectroscopic optical section, which will be described later, is connected to the emission section 145 when the optical device 1 for laser emission spectrometry is incorporated into the laser emission spectrometer 2 .

As shown in FIG. 1, it is preferable that the light receiving section 143 be placed near the condenser lens 13 so as not to block the laser light emitted from the laser oscillator 12. By locating the light receiving section 143 near the condensing lens 13, it becomes possible to receive more plasma light, and it becomes possible to further improve analysis accuracy.

The cylindrical probe 20 is a cylindrical member that has a probe part 21 and a base end part 23 that is provided on the base end side of the probe part 21 and fixes the probe part 21 to the housing 11.

The base end part 23 has a larger diameter than the probe part 21, supports the probe part 21 on the distal end side, and is fixed to the housing 11 on the base end side. Further, an inert gas inlet (gas inlet) 25 is arranged on the side surface of the base end portion 23, and the inert gas flows into the hollow portion of the cylindrical probe 20 through this gas inlet 25. Supplied.

The probe section 21 is a cylindrical member that forms an optical path between the object to be analyzed and the laser oscillator 12, and is arranged so that the open end 24 opens toward the object. When the object is molten metal, the tip of the probe section 21 is immersed in the molten metal. The pulsed laser beam irradiated from the laser oscillator 12 is guided by the probe section 21 and focused near the aperture end 24 (more preferably on the front side of the aperture end 24 in the laser beam traveling direction).

Furthermore, inert gas is supplied to the probe section 21 from the gas inlet 25 toward the open end 24, and is discharged from the open end 24 toward the target object. When the target object is irradiated with the laser light guided through the probe section 21, plasma is generated at the interface between the inert gas and the target object.

Here, the inert gas supply mechanism is not particularly limited, and known mechanisms such as an inert gas source and supply piping can be used. The supplied inert gas is preferably an inert gas commonly used in plasma emission analysis, such as Ar or He.

The cylindrical probe 20 has a cross section (more specifically, a cross section cut perpendicular to the central axis) of various shapes such as a square, a polygon, a circle, and an ellipse. It is a hollow member with a Further, in the cylindrical probe 20 according to this embodiment, the size of the cross section may not be constant along the central axis direction. For example, the cylindrical probe 20 is thick on the laser oscillator 12 side and the tip side of the cylindrical probe 20 is thin, or the cylindrical probe 20 is thin on the laser oscillator 12 side and the tip side of the cylindrical probe 20 is thick. It may be of any shape. However, considering that the laser beam is guided through the hollow portion, it is more preferable that the cylindrical probe 20 has a cylindrical shape.

The cylindrical probe 20 is connected to the housing 10 so that its central axis is parallel to the laser oscillation axis A of the laser beam emitted from the laser oscillator 12, and more preferably, its central axis is parallel to the laser oscillation axis A of the laser beam emitted from the laser oscillator 12. It is connected to the housing section 10 so as to be coaxial with the laser oscillation axis A of the laser light emitted from the laser oscillator 12 . Here, "the central axis of the cylindrical probe 20 is parallel to the laser oscillation axis A" means not only when the central axis of the cylindrical probe 20 and the laser oscillation axis A are completely parallel, but also when the central axis is parallel to the laser oscillation axis A. This also includes cases where the oscillation axis A is tilted by a certain permissible angle. Furthermore, "the central axis of the cylindrical probe 20 is coaxial with the laser oscillation axis A" means not only when the central axis and the laser oscillation axis A completely coincide, but also when the central axis is relative to the laser oscillation axis A. This also includes cases where it is sloped to some extent.

Specifically, in the above-mentioned "parallel" or "coaxial" mode, the permissible range of the angle between the laser oscillation axis A and the central axis of the cylindrical probe 20 is the angle between the cylindrical probe 20 and the target object. When the effective aperture diameter of is Deff (cm) and the distance from the laser oscillator 12 to the object is LL (cm), it is limited to less than arctan (Deff/LL). For example, when Deff and LL are 1.5 cm and 120 cm, respectively, the angle between the central axis of the cylindrical probe 20 and the laser oscillation axis A is limited to 0.36° or less.

Regarding the coaxiality of the laser oscillation axis A and the central axis of the cylindrical probe 20, each intersection of the extension line of the central axis of the cylindrical probe 20 on the surface of the condensing lens 13 on the laser oscillator 12 side and the laser beam It is sufficient that the maximum value of the distance between the two points is within Deff (cm), more preferably within 0.1×Deff (cm).

Note that the effective aperture diameter refers to the amount of coagulation that has adhered to the inner wall of the cylindrical probe 20 centered on the point where the central axis of the cylindrical probe 20 intersects with the object at the open end 24 of the cylindrical probe 20 on the object side. is the diameter of the largest circle not including Thereby, the laser beam emitted by the laser oscillator 12 is irradiated onto the target object through the cylindrical probe 20 without using a conventionally used laser reflecting mirror.

In general, the shorter the length of the cylindrical probe, the better from the viewpoints of ease of adjusting the optical axis of laser light and detection efficiency of plasma light. However, when the object to be analyzed is a high-temperature substance such as a molten metal, each component of the optical device 1 for laser emission spectroscopy is affected by radiant heat from the molten metal, which may affect analysis accuracy. The length of the cylindrical probe 20 (the length L in FIG. ) is preferably 60 cm or more and 150 cm or less. This makes it possible to achieve both ease of optical axis adjustment, plasma light detection efficiency, and prevention of deterioration in analysis accuracy. The length L of the cylindrical probe 20 is more preferably 70 cm or more and 300 cm or less, and still more preferably 80 cm or more and 150 cm or less.

Further, the diameter of the probe portion 21 (d1 in FIG. 1) is preferably, for example, 1.5 cm or more and 5.0 cm or less, and more preferably 2.5 cm or more and 3.5 cm or less. Thereby, even if the length L of the cylindrical probe 20 is relatively long as described above, it is possible to more reliably prevent the optical path of the laser beam from colliding with the inner wall of the cylindrical probe 20.

The inner wall near the open end 24 of the cylindrical probe 20 may have solidified matter or deposits derived from an object such as molten metal, and the laser beam may not be irradiated onto such solidified matter or deposits. This may make analysis difficult. Therefore, it is preferable to control the optical axis so that the irradiation point of the laser beam on the object is near the central axis of the cylindrical probe 20 (in other words, adjust the installation position of the laser oscillator 12).

The hood 30 is provided to cover the base end 23 of the cylindrical probe 20 and the housing 10 when viewed from the tip side of the cylindrical probe 20. By covering the base end 23 of the cylindrical probe 20 and the housing 10 with the hood 30, it is possible to suppress the influence of radiant heat from the object on the housing 10. Further, the hood 30 also functions as a flow path for a refrigerant (for example, cooling gas, etc.) supplied from the cooling mechanism 6, which will be described later.

As explained above, in the optical device 1 for laser emission spectroscopy according to the present embodiment, the laser oscillation axis A of the laser oscillator 12 and the central axis of the cylindrical probe 20 are substantially coaxial, and the light receiving section 143 is The light-receiving end face 144 is configured such that the surface normal direction thereof is substantially parallel to the laser oscillation axis A. This makes it possible to omit conventionally required components such as laser reflecting mirrors used to adjust the optical axis of laser light emitted from laser oscillators and optical members used to focus plasma light. becomes. Therefore, the optical device 1 for laser emission spectroscopy is lightweight and compact.

Although the optical device 1 for laser emission spectrometry according to the present embodiment can analyze any object, it is preferable that the object be molten metal, which is relatively high temperature. Molten metal has a relatively high temperature and has large temperature variations and temperature changes at the measurement site, so in order to obtain reliable analysis results, it is necessary to measure at a relatively deep position or at multiple positions. desired. Since the optical device 1 for laser emission spectroscopic analysis according to the present embodiment is lightweight and compact, it is also easy to move the optical device 1 for laser emission spectroscopic analysis and perform measurements on a plurality of measurement sites.

From the above, the optical device 1 for laser emission spectrometry analysis is suitable for equipment that handles molten metal, such as analysis of plating baths in molten metal plating equipment. Examples of the molten metal stored in the plating bath include molten zinc and molten aluminum.

<Modified example of optical device for laser emission spectroscopy>
Next, a modification of the optical device 1 for laser emission spectroscopy according to this embodiment will be described with reference to FIG. 2. FIG. 2 is an explanatory diagram schematically showing another example of the configuration of the optical device for laser emission spectroscopy according to the present embodiment.

The optical device 1A for laser emission spectrometry according to this modification differs from the optical device 1 for laser emission spectrometry shown in FIG. Below, the explanation will focus on such differences, and the explanation of similar matters will be omitted.

As described above, in the optical device 1A for laser emission spectroscopy according to this modification, the condenser lens 13 is arranged closer to the laser oscillator 12 than the light receiving section 143 of the optical fiber light receiving section 14 in the housing 11. . A light guiding window 15 is arranged on the cylindrical probe 20 side of the housing 11 instead of the condensing lens 13. An anti-reflection film for laser light is formed on the object-side surface 131 of the condenser lens 13 and the object-side surface 151 of the light guide window 15.

Also, in the above configuration, the laser oscillation axis A of the laser oscillator 12 and the central axis of the cylindrical probe 20 are approximately coaxial, and the surface normal of the light receiving end surface 144 of the light receiving section 143 of the optical fiber light receiving section 14 is The direction is configured to be substantially parallel to the laser oscillation axis A. Thereby, like the optical device 1 for laser emission spectrometry mentioned above, the optical device 1A for laser emission spectrometry becomes lightweight and small.

(About laser emission spectrometer)
Next, with reference to FIG. 3, the optical device 1 for laser emission spectrometry or the laser emission spectrometer 2 having the optical device 1A for laser emission spectroscopy according to the present embodiment will be described in detail. FIG. 3 is a block diagram schematically showing an example of the configuration of the laser emission spectrometer according to this embodiment.

As shown in FIG. 3, the laser emission spectrometer 2 according to the present embodiment includes an optical device 1 for laser emission spectrometry or an optical device 1A for laser emission spectrometry, a spectroscopic optical section 3, and a detector. 4 and an arithmetic processing unit 5. Moreover, it is preferable that the laser emission spectrometer 2 according to this embodiment further includes a cooling mechanism 6 as schematically shown in FIGS. 1 and 2.

Since the optical devices 1 and 1A for laser emission spectrometry have been previously described with reference to FIGS. 1 and 2, detailed description thereof will be omitted below.

The spectroscopic optics section 3 is connected to the optical fiber light receiving section 14 (more specifically, the emitting section 145) in the optical device 1, 1A for laser emission spectroscopic analysis, and is connected to the optical fiber light receiving section 14 (more specifically, the emitting section 145). ) to spectroscopy. The spectroscopic optical unit 3 is particularly limited as long as it has a resolution sufficient to separate light of each wavelength corresponding to the element to be analyzed (for example, in the case of molten zinc, at least Fe, Zn, and Al). Instead, it is possible to use various known spectroscopic optical elements such as a diffraction grating and a spectroscopic prism. Moreover, it is also possible to use various spectrometers as the spectroscopic optical section 3. The spectroscopic optical unit 3 separates the plasma light into respective wavelengths, which are detected by the detector 4 located at the subsequent stage.

The detector 4 is a device that detects the light emission (plasma light) separated by the spectroscopic optical unit 3, and detects the intensity of the light emission (plasma light) after the spectroscopy at each wavelength, and generates an electric signal corresponding to the intensity. Output. Examples of such a detector 4 include a CCD (Charge Coupled Device), an ICCD (Image intensifier Charge Coupled Device), and a CMOS (Complementary Device). Optical sensors such as ary Metal Oxide Semiconductor) and PMT (Photomultiplier Tube).

Among the above, it is more preferable to use an ICCD as the detector 4. The ICCD has particularly high sensitivity among the above-mentioned detectors. As described above, since the optical fiber light receiving unit 14 receives plasma light without condensing it, the amount of plasma light received is small compared to the case where conventional optical members are used to condense the light. . However, by using an ICCD as the detector 4, it is possible to accurately detect the intensity of the separated plasma light even with such a small amount of received light.

The detector 4 detects the intensity of a wavelength band that includes each wavelength corresponding to the target element of the object (for example, Fe, Zn, and Al in the case of molten zinc), and uses an electric signal corresponding to the intensity as detection data. The data is output to an arithmetic processing unit 5, which will be described later.

The arithmetic processing unit 5 centrally controls the operations of the laser emission spectroscopic analysis optical devices 1 and 1A, the spectroscopic optics section 3, and the detector 4 as described above, and also processes the detection data output from the detector 4. This is a device that performs spectroscopic analysis of objects based on The arithmetic processing unit 5 will be described in detail below with reference to FIG. FIG. 4 is a block diagram showing an example of the configuration of an arithmetic processing unit included in the laser emission spectrometer according to this embodiment.

As shown in FIG. 4, the arithmetic processing unit 5 according to the present embodiment mainly includes a control section 501, an arithmetic processing section 503, a result output section 507, a display control section 509, and a storage section 511. have.

The control unit 501 is realized by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input device, an output device, a communication device, and the like. The control unit 501 is a processing unit that centrally controls the functions of the laser emission spectroscopic analysis optical devices 1 and 1A, the spectroscopic optical unit 3, and the detector 4 according to this embodiment. Further, the control unit 501 can also control the functions of other mechanisms provided in the laser emission spectrometer 2, such as the cooling mechanism 6 described below, in an integrated manner.

More specifically, the control unit 501 controls the laser emission spectroscopic analysis optical devices 1 and 1A to start irradiating the laser light from the laser oscillator 12 when starting analysis of the target object. The signal is sent out, and the laser oscillator 12 irradiates the target object with laser light. Further, the control unit 501 sends a trigger signal to the spectroscopic optical unit 3 and the detector 4 to cause the received plasma light to be spectrally separated and output detection data regarding the intensity of each wavelength, and the detector 4 , outputs detection data regarding plasma light to the arithmetic processing unit 5.

The arithmetic processing unit 503 is realized by, for example, a CPU, ROM, RAM, communication device, etc. The calculation processing unit 503 is a processing unit that acquires detection data related to plasma light output from the detector 4 and performs various calculation processes on the detection data. This arithmetic processing section 503 has a component analysis section 505, as shown in FIG.

The component analysis unit 505 is realized by, for example, a CPU, ROM, RAM, etc. The component analysis unit 505 analyzes the components of the object based on the detection results of plasma light by the detector 4 (ie, detection data).

More specifically, the component analysis unit 505 performs component analysis using LIBS, for example, based on the detection results (ie, detection data) by the detector 4. Specifically, the component analysis unit 505 refers to the detection data and specifies which wavelength and intensity of light is detected. Then, the component analysis unit 505 refers to a database stored in the storage unit 511 or the like to identify what kind of component (element) the light of the wavelength of interest is derived from. Thereby, the components contained in the target object of interest can be specified.

Furthermore, the component analysis unit 505 can identify the content (concentration) of the identified component from data regarding the luminescence intensity included in the obtained detection data. This content may be calculated as a relative content from the luminescence intensity of each component identified as described above. In addition, for the components contained in the target object, a calibration curve showing the relationship between luminescence intensity and content is created in advance using standard reagents, etc., and the content of each component is calculated from the obtained luminescence intensity. It's okay.

After identifying the specific components contained in the object and their contents as described above, the component analysis unit 505 outputs the obtained results to the result output unit 507 as analysis results. Further, the component analysis unit 505 may store data regarding the acquired analysis results in the storage unit 511 as history information after associating the data with time information regarding the date and time when the data was acquired.

The result output unit 507 is realized by, for example, a CPU, ROM, RAM, output device, communication device, etc. The result output unit 507 outputs to the user of the laser emission spectrometer 2 information regarding the components of the object of interest, which is output from the arithmetic processing unit 503 (more specifically, the component analysis unit 505). Specifically, the result output unit 507 associates data regarding the analysis results of the components output from the calculation processing unit 503 with time data regarding the date and time when the data was generated, and outputs the data to various servers and control devices. Or output it as a paper medium using an output device such as a printer. Further, the result output unit 507 may output data regarding the analysis results to various information processing devices such as an external computer or to various recording media.

Additionally, the result output unit 507 can output data regarding the analysis results by the arithmetic processing unit 503 to the display control unit 509, which will be described later.

The display control unit 509 is realized by, for example, a CPU, ROM, RAM, output device, communication device, etc. The display control unit 509 displays the analysis results output from the result output unit 507 on an output device such as a display included in the laser emission spectrometer 2 or an output device provided outside the laser emission spectrometer 2. Performs display control at the time of display. Thereby, the user of the laser emission spectrometer 2 can grasp the analysis results for the components of the object of interest on the spot.

The storage unit 511 is an example of a storage device included in the laser emission spectrometer 2, and is realized by, for example, a ROM, a RAM, a storage device, or the like. The storage unit 511 stores various parameters that need to be saved when the laser emission spectrometer 2 according to the present embodiment performs some processing, and the progress of the processing (for example, various types of information stored in advance). data, database, programs, etc.) are recorded as appropriate. This storage unit 511 allows the control unit 501, arithmetic processing unit 503, component analysis unit 505, result output unit 507, display control unit 509, etc. to freely read/write data.

An example of the functions of the arithmetic processing unit 5 according to the present embodiment has been described above. Each of the above components may be constructed using general-purpose members and circuits, or may be constructed using hardware specialized for the function of each component. Further, the functions of each component may be entirely performed by a CPU or the like. Therefore, it is possible to change the configuration to be used as appropriate depending on the technical level at the time of implementing this embodiment.

Note that it is possible to create a computer program for realizing each function of the arithmetic processing unit according to the present embodiment as described above, and to implement it in a personal computer, a process computer that is a higher-level arithmetic processing device, or the like. Further, a computer-readable recording medium storing such a computer program can also be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

Further, the cooling mechanism 6 which is preferably included in the laser emission spectrometer 2 cools the devices inside the housing 10 including the laser oscillator 12 using a refrigerant. For example, when using cooled air as a refrigerant, the cooling mechanism 6 includes a blower and a blower pipe (not shown), and air outlets 61a and 61b, which are examples of refrigerant outlets, are provided at the ends of the stratified air pipes. is provided. At this time, as shown in FIGS. 1 and 2, an air outlet 61a that supplies the supplied refrigerant to the inside of the housing 11 and an air outlet that supplies the supplied refrigerant to the periphery of the housing 11 serve as the air outlet. It is preferable to provide an opening 61b.

The blowout port 61a is attached to the housing 11, thereby making it possible to supply refrigerant to the internal space 111 of the housing 11. The coolant supplied to the internal space 111 cools each device within the housing 11 , particularly the laser oscillator 12 , and is discharged from the opening 113 . On the other hand, the outlet 61b supplies refrigerant to the space between the hood 30 and the housing 11, for example. This makes it possible to cool the housing 11 from the outside.

As a result, each device in the casing 11 is cooled by the double cooling mechanism, efficiently blocking heat from the object, and efficiently cooling each device in the casing 11.

In addition, although the embodiment using air cooling as the cooling mechanism was described above, the present invention is not limited to this, and the cooling mechanism may include liquid cooling such as water cooling, electronic cooling using a thermoelectric element such as a Peltier element, etc. Various cooling mechanisms may be employed. Furthermore, a combination of a plurality of cooling mechanisms may be used.

(About the hardware configuration of the arithmetic processing unit 5)
Next, the hardware configuration of the arithmetic processing unit 5 according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 is a block diagram for explaining the hardware configuration of the arithmetic processing unit 5 according to this embodiment.

The arithmetic processing unit 5 mainly includes a CPU 901, a ROM 903, and a RAM 905. The arithmetic processing unit 5 further includes a bus 907, an input device 909, an output device 911, a storage device 913, a drive 915, a connection port 917, and a communication device 919.

The CPU 901 functions as a central processing device and control device, and controls the entire operation or a part of the operation within the arithmetic processing unit 5 according to various programs recorded in the ROM 903, RAM 905, storage device 913, or removable recording medium 921. do. The ROM 903 stores programs, calculation parameters, etc. used by the CPU 901. The RAM 905 temporarily stores programs used by the CPU 901 and parameters that change as appropriate during program execution. These are interconnected by a bus 907 constituted by an internal bus such as a CPU bus.

The bus 907 is connected to an external bus such as a PCI (Peripheral Component Interconnect/Interface) bus via a bridge.

The input device 909 is, for example, an operation means operated by the user, such as a mouse, keyboard, touch panel, button, switch, or lever. Further, the input device 909 may be, for example, a remote control means (so-called remote control) using infrared rays or other radio waves, or an external connection device 923 such as a PDA that is compatible with the operation of the arithmetic processing unit 5. It's okay. Further, the input device 909 includes, for example, an input control circuit that generates an input signal based on information input by the user using the above-mentioned operating means and outputs it to the CPU 901. By operating this input device 909, the user can input various data to the arithmetic processing unit 5 and instruct processing operations.

The output device 911 is a device that can visually or audibly notify the user of the acquired information. Examples of such devices include display devices such as CRT display devices, liquid crystal display devices, plasma display devices, EL display devices, and lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, and facsimiles. The output device 911 outputs, for example, results obtained by various processes performed by the arithmetic processing unit 5. Specifically, the display device displays the results obtained by various processes performed by the arithmetic processing unit 5 in text or images. On the other hand, the audio output device converts an audio signal consisting of reproduced audio data, audio data, etc. into an analog signal and outputs the analog signal.

The storage device 913 is a data storage device configured as an example of a storage section of the arithmetic processing unit 5. The storage device 913 is configured of, for example, a magnetic storage device such as a HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like. This storage device 913 stores programs executed by the CPU 901, various data, and various data acquired from the outside.

The drive 915 is a reader/writer for recording media, and is either built into the arithmetic processing unit 5 or attached externally. The drive 915 reads information recorded on an attached removable recording medium 921 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, and outputs it to the RAM 905. The drive 915 can also write records on a removable recording medium 921, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. The removable recording medium 921 is, for example, CD media, DVD media, Blu-ray (registered trademark) media, or the like. Further, the removable recording medium 921 may be a CompactFlash (CF), a flash memory, an SD memory card (Secure Digital memory card), or the like. Furthermore, the removable recording medium 921 may be, for example, an IC card (Integrated Circuit card) equipped with a non-contact IC chip, an electronic device, or the like.

The connection port 917 is a port for directly connecting a device to the arithmetic processing unit 5. Examples of the connection ports 917 include a USB (Universal Serial Bus) port, an IEEE1394 port, a SCSI (Small Computer System Interface) port, an RS-232C port, and an HDMI (registered trademark) (High-Def Initiation Multimedia Interface) port, etc. By connecting the externally connected device 923 to this connection port 917, the arithmetic processing unit 5 can directly acquire various data from the externally connected device 923 or provide various data to the externally connected device 923.

The communication device 919 is, for example, a communication interface configured with a communication device for connecting to the communication network 925. The communication device 919 is, for example, a communication card for wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), or WUSB (Wireless USB). Further, the communication device 919 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), a modem for various communications, or the like. This communication device 919 can transmit and receive signals, etc., to and from the Internet or other communication devices, for example, in accordance with a predetermined protocol such as TCP/IP. Further, the communication network 925 connected to the communication device 919 is configured by a wired or wirelessly connected network, and may be, for example, the Internet, a home LAN, an in-house LAN, infrared communication, radio wave communication, or satellite communication. It's okay.

An example of the hardware configuration capable of realizing the functions of the arithmetic processing unit 5 according to the embodiment of the present invention has been described above. Each of the above components may be constructed using general-purpose members, or may be constructed using hardware specialized for the function of each component. Therefore, it is possible to change the hardware configuration to be used as appropriate depending on the technical level at the time of implementing this embodiment.

(Hot dip metal plating equipment)
Next, an example of molten metal plating equipment equipped with the above-mentioned laser emission spectrometer will be described. FIG. 6 is a side view showing a schematic configuration of the hot-dip galvanizing apparatus according to this embodiment. Note that as an example of a molten metal bath, a representative hot-dip galvanizing bath 701 (hereinafter also simply referred to as a "plating bath") in a hot-dip galvanizing facility 700 will be described, but the present invention is limited to such an example. However, it is possible to apply to any other molten metal bath.

The hot-dip galvanizing equipment 700 is equipment for continuously depositing molten zinc on the surface of the steel strip S by immersing the steel strip S in a plating bath 701 filled with molten zinc. The hot-dip galvanizing equipment 700 includes a plating tank 703, a snout 705, a roll in the bath 707, a support roll 709, an inductor 711, a gas wiping device 713, an alloying furnace 715, and a laser emission spectrometer 2.

A plating bath 703 stores a plating bath 701 made of molten zinc. In addition, in addition to Zn, the plating bath 701 according to the present embodiment contains, for example, about 0.12 to 0.15% by mass of Al and about 0.02 to 0.1% by mass of Fe. ing. Further, the temperature of the plating bath 701 is, for example, about 440 to 480°C. The snout 705 is arranged at an angle so that one end thereof is immersed in the plating bath 701. The bath roll 707 is disposed at the lowermost position inside the plating tank 703. The bath roll 707 rotates along the illustrated arrow due to contact with the steel strip S and shearing.

The support roll 709 is arranged inside the plating tank 703 on the downstream side of the submerged roll 707 in the conveyance direction of the steel strip S, and is arranged so as to sandwich the steel strip S sent out from the submerged roll 707 from both left and right sides. will be established. The support roll 709 is rotatably supported by a bearing (for example, a sliding bearing, a rolling bearing, etc.) not shown. Note that only one support roll, three or more support rolls, or no support rolls may be installed.

The inductor 711 is an example of a heating device that heats the plating bath 701 filled in the plating tank 703. As shown in FIG. 6, a plurality of inductors 711 according to this embodiment are provided on the side wall of the plating bath 703 to adjust the bath temperature of the plating bath 701. Note that the heating means for heating the plating bath 701 is not limited to such an inductor 711, and a known technique can be used.

The gas wiping device 713 is disposed above the plating tank 703, and blows gas (e.g., nitrogen, air) onto both surfaces of the steel strip S to scrape off molten metal adhering to the surface of the steel strip S. It has the function of controlling the amount of molten metal deposited.

The alloying furnace 715 is an example of a heating device that heats the steel strip S after gas wiping to a predetermined temperature. The alloying furnace 715 increases the temperature of the steel strip S by heating, and promotes alloying of the plating layer of molten metal attached to the surface of the steel strip S. Note that as the alloying furnace 715, for example, a known technique such as an induction heating type heater is used.

The steel strip S that has been annealed in the annealing furnace that is an upstream process is immersed in a plating tank 703 filled with a plating bath 701 via a snout 705, passes through a bath roll 707 and a support roll 709, and is pulled up in the vertical direction. and transported outside the plating bath 701. The steel strip S transported outside the plating bath 701 passes through an alloying furnace 715 after the basis weight of the molten metal adhering to the surface is adjusted by a gas wiping device 713.

The laser emission spectrometer 2 is a device that has the function of detecting and analyzing each component present in the plating bath 701. The laser emission spectrometer 2 quantifies the content of, for example, Fe and Al from the signal intensity data of the target elements obtained by irradiating the plating bath 701 with a pulsed laser while supplying an inert gas. That is, the laser emission spectrometer 2 according to the present embodiment has a configuration for performing the LIBS method using a hot-dip zinc plating bath as the measurement target.

An example of hot-dip metal plating equipment to which the laser emission spectrometer of the present invention is applied has been described above.

(About laser emission spectroscopy method)
Next, a laser emission spectroscopic analysis method according to this embodiment will be explained. The laser emission spectrometry method according to the present embodiment is a method for analyzing molten metal in a plating bath for molten metal plating using the laser emission spectrometer of the present invention.

In the following, a case will be exemplified in which hot-dip galvanizing in the hot-dip galvanizing equipment 700 described above is analyzed as hot-dip metal plating using the laser emission spectrometer 2 equipped with the optical device 1 for laser emission spectroscopy described above. Give an explanation.

First, the laser oscillator 12 of the housing 10 included in the optical device 1 for laser emission spectroscopy oscillates a laser beam under the control of the arithmetic processing unit 5. The oscillated laser light is focused by the condensing lens 13, guided by the cylindrical probe 20, and focused near the opening end 24. Furthermore, an inert gas such as Ar is supplied from the gas inlet 51 of the cylindrical probe 20 toward the open end 24 . Then, the laser beam is irradiated onto the object, molten metal (Fe, Zn, Al, etc.) in the plating bath 701. As a result, plasma is generated at the interface between the inert gas and the molten metal, and plasma light is generated accordingly.

The generated plasma light is guided in the cylindrical probe 20, and a part of it is not focused on the optical fiber light receiving section 14 (more specifically, the light receiving end surface 144 of the light receiving section 143) in the housing section 10. ) is received by the The received plasma light is guided to the spectroscopic optical section 3 via the bundle fiber 141 and the output section 145. The spectroscopic optical section 3 separates the guided plasma light into each wavelength under the control of the arithmetic processing unit 5, and the separated plasma light reaches the detector 4 at the subsequent stage. The detector 4 detects the separated plasma light for each wavelength under the control of the arithmetic processing unit 5, and measures the intensity of the plasma light at each wavelength. Thereafter, the detector 4 outputs an electrical signal corresponding to the intensity of the plasma light to the arithmetic processing unit 5 as measurement data. As a result, the intensity of plasma light derived from each component such as Fe, Zn, and Al contained in the plating bath 701 is specified.

A component analysis section 505 provided in the arithmetic processing unit 5 performs a known method using measurement data including electrical signals corresponding to the intensity of plasma light derived from each component such as Fe, Zn, and Al as described above. The content (concentration) of each component such as Fe, Zn, and Al is analyzed. This makes it possible to grasp the content (concentration) of each component such as Fe, Zn, and Al in the plating bath 701 of interest.

At this time, for example, hot-dip galvanizing with different Al concentrations is measured using the analysis method according to the present embodiment to obtain the emission intensity ratio I(Al)/I(Zn) of Al and Zn, and A calibration curve showing the relationship between the Al concentration and the above luminescence intensity ratio is prepared in advance by sampling a part of the aluminum, dissolving it in acid, and quantifying it by ICP emission spectrometry, etc. , stored in the storage unit 511. The component analysis unit 505 uses the acquired measurement data and the calibration curve to convert the luminescence intensity ratio I(Al)/I(Zn) calculated from the measurement data into the Al concentration in molten zinc. I can do it.

In addition, in this embodiment, since the laser emission spectrometer 2 has the above-described configuration, a part of the generated plasma light is received by the optical fiber light receiving section 14 without condensing it, and the detector 4 It is possible to detect light of each wavelength corresponding to each component of molten metal such as Fe, Zn, and Al. As a result, it is possible to suppress the effects of thermal distortion of the hot-dip galvanizing equipment 700, vibration, and bath surface fluctuations on the analysis results, and it is possible to analyze each component with relatively high accuracy over a long period of time.

Furthermore, the optical device 1 for laser emission spectrometry included in the laser emission spectrometer 2 has the above-described configuration, thereby making it possible to omit optical members for condensing plasma light and adjusting the oscillation axis of laser light. It is significantly smaller and lighter than conventional optical devices for laser emission spectroscopy. This makes it easier to perform analysis in locations where conventional methods cannot be placed due to narrow spaces, or to change measurement points.

Hereinafter, the optical device for laser emission spectrometry, the laser emission spectrometer, the method for laser emission spectrometry, and the molten metal plating equipment according to the present embodiment will be explained while showing specific examples.

First, an optical device for laser emission spectrometry corresponding to the optical device 1 for laser emission spectrometry shown in FIG. 1 was manufactured. The specific device configuration and measurement conditions are as follows.

(laser)
Laser oscillator: LumiBird Viron (diode pumped Nd:YAG laser)
Laser oscillation conditions: wavelength 1064nm, 20Hz, 50mJ/pulse
(Condenser lens)
Focal length: 900mm
Note that an antireflection film corresponding to the wavelength of the laser beam was provided on the surface of the condensing lens on the laser oscillator side.
(Optical fiber receiver)
Optical fiber (manufactured by Mitsubishi Cable Co., Ltd., type 1 standard fiber 15m (32 cores))
(cooling mechanism)
Air cooling method using compressed air

(Spectroscopic optics section, detector)
The following spectrometer was used as the spectroscopic optical unit and detector.
Spectrometer: SOL instrument double grating spectrometer (NP250-2) TOP: 600 lines/mm, BOTTOM: 1200 lines/mm, slit width: 30 μm
Detector: Andor ICCD camera (istar, gain: 2000, gate width: 10000ns, delay: 1000ns, number of integrations: 1 time, number of repetitions: 1 time)

(cylindrical probe)
Cylindrical probe length: 1000mm
Probe material: Sialon (silicon nitride)

Further, as an inert gas, pure Ar gas with a purity of 99.9999% or more was used and was supplied to the cylindrical probe at a flow rate of 1.0 L/min.

In the above configuration, the laser oscillation axis and the central axis of the cylindrical probe are parallel to each other, and the normal direction of the light receiving end face of the optical fiber receiver and the laser oscillation axis are also parallel to each other. did.

The dimensions of the casing of the optical device for laser emission spectroscopy produced as described above were 330 mm (width) x 220 mm (height) x 200 mm (depth). In the case of a conventional configuration in which mirrors are arranged for optical axis adjustment, the limit for miniaturization is approximately 500 mm (width) x 250 mm (height) x 640 mm (depth). As a result, the manufactured optical device for laser emission spectroscopy can be significantly reduced in size and, accordingly, also achieved a reduction in weight.

A laser emission spectrometer was configured using the fabricated optical device for laser emission spectrometry, and the spectral intensity of Zn and Al in the molten zinc bath was measured over time by setting the cumulative time of the detected signal (signal intensity) to 300 seconds. I did it. FIG. 7 shows a laser-induced breakdown spectrum (LIBS spectrum) of the molten zinc bath measured under the above conditions.

Among the spectra shown in FIG. 7, FIG. 8 shows a time course in which the 307.6 nm signal corresponding to the emission wavelength of Al is normalized by the 307.3 nm signal corresponding to the emission wavelength of Zn.

The measured Al concentration in the molten zinc bath was not intentionally changed and can be assumed to be constant over time. As shown in FIG. 8, the Al/Zn peak ratio (signal intensity ratio) was almost constant. As described above, it has been shown that the laser emission spectrometer according to the present embodiment can accurately quantify the components of molten metal over time.

On the other hand, when we conducted a similar experiment using an optical device for laser emission spectrometry that uses a lens to condense the plasma light and makes it incident on the light receiving section, we found that the above-mentioned condensed light was observed after about one day of measurement. The variation in the Al/Zn peak ratio (signal intensity ratio) was about twice that of the present invention in which no This suggests that the configuration of the present invention, which receives plasma light without condensing it, actually improves measurement accuracy.

Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

The embodiments disclosed herein are illustrative in all respects and are not restrictive. The above-described embodiments may be omitted, replaced, or modified in various forms without departing from the scope of the appended claims and the configurations and gist of the present invention as described below. For example, the constituent features of the above embodiments can be combined arbitrarily within a range that does not impair the effects. Further, from the arbitrary combination, the functions and effects of the respective constituent elements related to the combination can be obtained as a matter of course, and other functions and other effects that are obvious to a person skilled in the art from the description of this specification can be obtained. .

Furthermore, the effects described in this specification are merely explanatory or illustrative, and are not limiting. In other words, the technology according to the present invention can produce other effects that are obvious to those skilled in the art from the description of this specification, in addition to or in place of the above effects.

1, 1A Optical device for laser emission spectrometry analysis 2 Laser emission spectrometer 3 Spectroscopic optical section 4 Detector 5 Arithmetic processing unit 6 Cooling mechanism 10 Housing section 11 Housing 12 Laser oscillator 13 Condensing lens 14 Optical fiber light receiving section 20 Tube shaped probe 21 probe part 23 base end 24 open end 25 gas inlet 30 hood 61a, 61b refrigerant outlet 111 internal space
113 Opening 141 Bundle Fiber 143 Human Pack 145 Exit 145 Hine Exit Balesis 501 Control Department 501 Balant Processing Department 505 Component Analysis Department 505 Results Output Department 509 Division Output Department 501 Division Control Department 700 Memorial Zalin Putching Facilities 701 Meiki Bath 705 Squeezing tank 705 World 707 Roll in bath 709 Support roll 711 Inductor 713 Gas wiping device 715 Alloying furnace S Steel strip

Claims (14)

1. An optical device used for analyzing the components of molten metal, the optical device comprising:
   A laser oscillator that emits laser light,
   one condensing lens that condenses the laser beam and into which the laser beam emitted from the laser oscillator directly enters;
   an optical fiber light receiving section that receives light emitted from plasma generated by irradiating the molten metal with the laser light at a light receiving end surface;
   a casing portion having;
   The device is connected to the casing so that its central axis is parallel to the oscillation axis of the laser beam in the laser oscillator, and supplies inert gas toward an open end located downstream in the direction of travel of the laser beam. and a cylindrical probe that guides the laser beam to the open end and irradiates the molten metal;
   Equipped with
   An optical device for laser emission spectroscopy, wherein a surface normal direction of the light receiving end face of the optical fiber light receiving section is parallel to an oscillation axis of the laser beam.
2. The optical device for laser emission spectroscopy according to claim 1, wherein the cylindrical probe is connected to the housing portion so that its central axis is coaxial with the oscillation axis of the laser beam.
3. The optical device for laser emission spectroscopy according to claim 1 or 2, wherein the condensing lens is provided at a connection portion between the housing portion and the cylindrical probe.
4. The optical device for laser emission spectroscopy according to any one of claims 1 to 3, wherein at least a part of the emitted light is incident on the light receiving end face of the optical fiber light receiving section in an uncondensed state.
5. The optical device for laser emission spectroscopy according to any one of claims 1 to 4, wherein the laser oscillator is a diode-excited laser oscillator.
6. The optical device for laser emission spectroscopy according to any one of claims 1 to 5, wherein the condenser lens has an antireflection film on its surface that prevents reflection of the laser beam.
7. The optical system for laser emission spectrometry analysis according to any one of claims 1 to 6, further comprising an angle adjustment mechanism that adjusts a lens optical axis direction of the condenser lens by changing an attachment angle of the condenser lens. Device.
8. The optical device for laser emission spectroscopy according to any one of claims 1 to 7,
   a spectroscopic optical unit that spectrally spectra the light emission guided by the optical fiber light receiving unit;
   a detector that detects the light emitted spectrally separated by the spectroscopic optical unit;
   a component analysis unit that analyzes the components of the molten metal based on the detection result of the light emission by the detector;
   A laser emission spectrometer equipped with.
9. The laser emission spectrometer according to claim 8, wherein the detector is an image intensifier charge-coupled device detector.
10. The laser emission spectrometer according to claim 8 or 9, further comprising a cooling mechanism that cools the inside of the casing.
11. A method for laser emission spectrometry, comprising analyzing molten metal in a plating bath for molten metal plating using the laser emission spectrometer according to any one of claims 8 to 10.
12. The laser emission spectroscopy method according to claim 11, wherein the hot-dip metal plating is hot-dip galvanizing.
13. A molten metal plating facility comprising the laser emission spectrometer according to any one of claims 8 to 10.
14. The hot-dip metal plating equipment according to claim 13, which is a hot-dip galvanizing equipment for performing hot-dip galvanizing.

Images